I cannot but look upon the strange Instinct of this noisome and troublesome Creature a Louse, of searching out foul and nasty Clothes to harbor and breed in, as an Effect of divine Providence, design'd to deter Men and Women from Sluttishness and Sordidness.

There is no doubt, that man is not built to be a carnivorous animal... What a sweet, pleasing and innocent sight is the spectacle of a table served that way and what a difference to a make up of fuming animal meat, slaughtered and dead! Man in no way has the constitution of a carnivorous being. Hunt and voracity are unnatural to him. Man has neither the sharp pointed teeth or claws to slaughter his prey. On the contrary his hands are made to pick fruits, berries and vegetables and teeth appropriate to chew them.

I do not know who first emphasized the need for a clear understanding of the sense in which the term species is to be applied. In the second half of the seventeenth century Ray shows some degree of concern on this matter. In the introduction to the Historia Plantarum, 1686, he discusses some of the difficulties and lays down the principle that varieties which can be produced from the seed of the same plant are to be regarded as belonging to one species, being, I believe, the first to suggest this definition.